@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Space+Grotesk:wght@400;500;600&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  --color-canvas: #05060f;
  --color-steel: #2f343e;
  --color-fog: #9da7ba;
  --color-mist: #c7d3ea;
  --color-frost: #d1e4fa;
  --color-ice: #d8ecf8;
  --color-white: #ffffff;
  --color-violet: #663af3;
  --color-blueprint: #b6d9fc;
  --border-frost: rgba(186,215,247,0.12);
  --fill-frost: rgba(186,214,247,0.06);
  --fill-frost-soft: rgba(186,214,247,0.03);

  --font-sans: 'Inter', ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-display: 'Space Grotesk', var(--font-sans);
  --font-mono: 'JetBrains Mono', ui-monospace, "SF Mono", Menlo, monospace;

  --page-max-width: 1200px;
  --section-gap: 100px;
  --radius-card: 16px;
  --radius-badge: 6px;
  --radius-pill: 999px;
}

* { box-sizing: border-box; }

body {
  font-family: var(--font-sans);
  color: var(--color-mist);
  background: var(--color-canvas);
  margin: 0;
  line-height: 1.5;
  position: relative;
}

/* blueprint grid + spotlight, full-bleed ambient layer */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(var(--border-frost) 1px, transparent 1px),
    linear-gradient(90deg, var(--border-frost) 1px, transparent 1px);
  background-size: 88px 88px;
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 40%, transparent 85%);
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 40%, transparent 85%);
}
body::after {
  content: "";
  position: fixed;
  top: -10%;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 500px;
  z-index: 0;
  pointer-events: none;
  background: radial-gradient(ellipse at center, rgba(124,145,182,0.28) 0%, transparent 70%);
}

img, svg { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }

/* Header */
.masthead {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(5,6,15,0.75);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-frost);
}
.masthead-inner {
  max-width: var(--page-max-width);
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}
.brand {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 16px;
  color: var(--color-frost);
}
.primary-nav { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.primary-nav a.link {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-mist);
  padding: 8px 12px;
  border-radius: var(--radius-pill);
}
.primary-nav a.link:hover { color: var(--color-white); background: var(--fill-frost); }
.pill {
  display: inline-block;
  border-radius: var(--radius-pill);
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid var(--border-frost);
  background: var(--fill-frost);
  color: var(--color-white);
}
.pill:hover { background: rgba(186,214,247,0.12); }

.page { position: relative; z-index: 1; max-width: var(--page-max-width); margin: 0 auto; padding: 0 24px; }

/* Hero */
.hero { padding: 72px 0 40px; text-align: center; }
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--color-mist);
  margin: 0 0 28px;
}
.eyebrow::before, .eyebrow::after { content: ""; width: 40px; height: 1px; background: linear-gradient(90deg, transparent, var(--border-frost)); }
.eyebrow::after { background: linear-gradient(90deg, var(--border-frost), transparent); }
.hero h1 {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 52px;
  line-height: 1.14;
  margin: 0 auto 20px;
  max-width: 780px;
  background: linear-gradient(180deg, var(--color-ice) 0%, #98c0ef 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
@media (max-width: 700px) { .hero h1 { font-size: 34px; } }
.hero p.subhead {
  font-size: 16px;
  color: var(--color-mist);
  max-width: 560px;
  margin: 0 auto 32px;
}

/* Floating device cards */
.float-cards {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: -20px;
  padding: 40px 0 20px;
  flex-wrap: wrap;
}
.float-card {
  width: 240px;
  background: rgba(5,6,15,0.97);
  border-radius: var(--radius-card);
  padding: 24px;
  box-shadow: inset 0 1px 1px rgba(216,236,248,0.2), inset 0 24px 48px rgba(168,216,245,0.06), 0 16px 32px rgba(0,0,0,0.4);
  text-align: left;
  margin: 0 -14px;
}
.float-card.tilt-left { transform: rotate(-4deg) translateY(10px); }
.float-card.tilt-right { transform: rotate(4deg) translateY(10px); }
.float-card.tilt-center { transform: scale(1.08); z-index: 2; }
.float-card .tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--color-frost);
  background: rgba(199,211,234,0.12);
  border-radius: var(--radius-badge);
  padding: 3px 8px;
  margin-bottom: 14px;
}
.float-card h4 { font-family: var(--font-display); font-size: 17px; font-weight: 500; color: var(--color-ice); margin: 0 0 6px; }
.float-card p { font-size: 13px; color: var(--color-fog); margin: 0; line-height: 1.45; }

.cta-row { display: flex; justify-content: center; gap: 12px; margin: 16px 0 0; flex-wrap: wrap; }

/* Section */
.section { padding: var(--section-gap) 0; }
.section-head { text-align: center; max-width: 640px; margin: 0 auto 48px; }
.section h2 {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 36px;
  color: var(--color-ice);
  margin: 0 0 14px;
  line-height: 1.16;
}
.section-head p { font-size: 16px; color: var(--color-fog); margin: 0; }

/* Icon tile row */
.icon-row {
  display: flex;
  justify-content: center;
  gap: 28px;
  flex-wrap: wrap;
  padding: 8px 0 40px;
}
.icon-tile { text-align: center; width: 100px; display: block; }
.icon-tile:hover .circle { background: rgba(186,214,247,0.14); border-color: rgba(186,215,247,0.28); }
.icon-tile:hover span { color: var(--color-white); }
.icon-tile .circle {
  width: 60px; height: 60px;
  border-radius: 9999px;
  background: var(--fill-frost);
  border: 1px solid var(--border-frost);
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 12px;
}
.icon-tile .circle svg { width: 26px; height: 26px; stroke: var(--color-frost); }
.icon-tile span { font-size: 13px; color: var(--color-mist); }

/* Glass feature cards */
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
@media (max-width: 900px) { .card-grid { grid-template-columns: 1fr; } }
.glass-card {
  background: var(--fill-frost-soft);
  border-radius: var(--radius-card);
  padding: 24px;
  box-shadow: inset 0 0 0 1px var(--border-frost);
}
.glass-card .icon { width: 40px; height: 40px; border-radius: 9999px; background: var(--fill-frost); display: flex; align-items: center; justify-content: center; margin-bottom: 16px; }
.glass-card .icon svg { width: 20px; height: 20px; stroke: var(--color-frost); }
.glass-card h3 { font-family: var(--font-display); font-size: 19px; font-weight: 500; color: var(--color-ice); margin: 0 0 8px; }
.glass-card p { font-size: 14px; color: var(--color-fog); margin: 0; line-height: 1.55; }
.glass-card a.more { display: inline-block; margin-top: 14px; font-size: 13px; color: var(--color-frost); border-bottom: 1px solid var(--border-frost); }

/* Photo band (real stock photo, dark-treated) */
.photo-band {
  position: relative;
  border-radius: var(--radius-card);
  overflow: hidden;
  box-shadow: inset 0 0 0 1px var(--border-frost);
  min-height: 320px;
  display: flex;
  align-items: flex-end;
}
.photo-band img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.photo-band-content {
  position: relative; z-index: 1; margin: 24px;
  background: rgba(5,6,15,0.82);
  backdrop-filter: blur(6px);
  border: 1px solid var(--border-frost);
  border-radius: var(--radius-card);
  padding: 24px 28px;
  max-width: 480px;
}
.photo-band-content .tag { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.06em; color: var(--color-frost); margin: 0 0 10px; }
.photo-band-content h3 { font-family: var(--font-display); font-size: 24px; font-weight: 500; color: var(--color-ice); margin: 0 0 8px; }
.photo-band-content p { font-size: 14px; color: var(--color-mist); max-width: 520px; margin: 0; }

/* Table (protocol spec) */
.specs { border-radius: var(--radius-card); background: var(--fill-frost-soft); box-shadow: inset 0 0 0 1px var(--border-frost); overflow: hidden; }
.spec-row { display: flex; justify-content: space-between; padding: 16px 24px; border-top: 1px solid var(--border-frost); font-size: 14px; }
.spec-row:first-child { border-top: none; }
.spec-label { color: var(--color-fog); }
.spec-value { color: var(--color-frost); font-family: var(--font-mono); font-size: 13px; }

/* Footer */
.site-footer {
  position: relative; z-index: 1;
  border-top: 1px solid var(--border-frost);
  padding: 28px 24px;
  max-width: var(--page-max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}
.footer-nav { display: flex; gap: 20px; flex-wrap: wrap; }
.footer-nav a, .copyright { font-size: 13px; color: var(--color-fog); }

/* Articles */
.breadcrumb { position: relative; z-index: 1; font-size: 13px; color: var(--color-fog); padding: 24px 0 0; }
.breadcrumb a { color: var(--color-fog); }
.breadcrumb a:hover { color: var(--color-frost); }
.article { position: relative; z-index: 1; max-width: 740px; margin: 0 auto; padding: 32px 0 80px; }
.article .eyebrow { justify-content: flex-start; }
.article h1 {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 38px;
  line-height: 1.14;
  color: var(--color-ice);
  margin: 0 0 16px;
}
@media (max-width: 700px) { .article h1 { font-size: 28px; } }
.article .dek { font-size: 17px; color: var(--color-fog); margin: 0 0 32px; }
.article h2 {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 24px;
  color: var(--color-ice);
  margin: 40px 0 16px;
}
.article p { font-size: 16px; line-height: 1.65; color: var(--color-mist); margin: 0 0 16px; }
.article ul, .article ol { margin: 0 0 16px; padding-left: 22px; }
.article li { font-size: 16px; line-height: 1.65; color: var(--color-mist); margin-bottom: 8px; }
.article p a, .article li a { color: var(--color-frost); text-decoration: underline; text-underline-offset: 2px; }
.article p a:hover, .article li a:hover { color: var(--color-ice); }
.article a.guide-card, .article a.more { text-decoration: none; }
.article figure.photo {
  border-radius: var(--radius-card);
  overflow: hidden;
  box-shadow: inset 0 0 0 1px var(--border-frost);
  margin: 24px 0;
}
.article figure.photo img { width: 100%; }
.article figure.photo figcaption {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-fog);
  padding: 10px 16px;
  border-top: 1px solid var(--border-frost);
}
.article .note {
  background: var(--fill-frost-soft);
  border-radius: var(--radius-card);
  box-shadow: inset 0 0 0 1px var(--border-frost);
  padding: 20px 24px;
  font-size: 15px;
  color: var(--color-mist);
  margin: 24px 0;
}
.guide-grid { position: relative; z-index: 1; display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
@media (max-width: 900px) { .guide-grid { grid-template-columns: 1fr; } }
.guide-card {
  background: var(--fill-frost-soft);
  border-radius: var(--radius-card);
  box-shadow: inset 0 0 0 1px var(--border-frost);
  padding: 24px;
}
.guide-card .tag { display: inline-block; font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.04em; color: var(--color-frost); background: rgba(199,211,234,0.12); border-radius: var(--radius-badge); padding: 3px 8px; margin-bottom: 14px; }
.guide-card h3 { font-family: var(--font-display); font-size: 19px; font-weight: 500; color: var(--color-ice); margin: 0 0 8px; }
.guide-card p { font-size: 14px; color: var(--color-fog); margin: 0; line-height: 1.55; }

/* Header dropdown (native <details>, no JS) */
.dropdown { position: relative; }
.dropdown summary {
  cursor: pointer;
  list-style: none;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-mist);
  padding: 8px 12px;
  border-radius: var(--radius-pill);
  display: flex;
  align-items: center;
  gap: 6px;
}
.dropdown summary::-webkit-details-marker { display: none; }
.dropdown summary::after {
  content: "";
  width: 6px; height: 6px;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  transform: rotate(45deg) translateY(-2px);
  transition: transform 0.15s ease;
}
.dropdown[open] summary::after { transform: rotate(-135deg) translateY(2px); }
.dropdown summary:hover, .dropdown[open] summary { color: var(--color-white); background: var(--fill-frost); }
.dropdown-panel {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  min-width: 200px;
  background: rgba(5,6,15,0.97);
  border: 1px solid var(--border-frost);
  border-radius: var(--radius-card);
  padding: 8px;
  box-shadow: 0 16px 32px rgba(0,0,0,0.5);
  z-index: 30;
}
.dropdown-panel a {
  display: block;
  padding: 9px 12px;
  border-radius: 8px;
  font-size: 14px;
  color: var(--color-mist);
}
.dropdown-panel a:hover { background: var(--fill-frost); color: var(--color-white); }

/* Category hub pages */
.category-hero { padding: 56px 0 40px; }
.category-hero h1 { font-family: var(--font-display); font-weight: 500; font-size: 40px; color: var(--color-ice); margin: 16px 0; }
.category-hero p { font-size: 17px; color: var(--color-fog); max-width: 640px; margin: 0; }
.related-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 16px; }
.related-row a {
  font-size: 13px;
  color: var(--color-mist);
  border: 1px solid var(--border-frost);
  border-radius: var(--radius-pill);
  padding: 6px 14px;
}
.related-row a:hover { color: var(--color-white); background: var(--fill-frost); }